As I’m waiting for the M21K LHP73B, I keep thinking about SFT90 version or a modded SBT90.2 flavour of it.
All other aspects aside, I was curious how these three could compare thermally.
So I looked at @koef3’s tests of the three (the SBT90.2 is not on the master list).
From the 1Lumen review of the LHP73B I figured the TIR efficiency may be some 85% and assumed it applies to other emitters. Then also assumed that the output current to the LEDs on turbo and super-turbo is the nominal 10 A and 20 A (as @thefreeman measured above in this thread for LHP73B) for all on a fresh tabless battery.
| Output/Power | LHP73B | SBT90.2 | SFT90 |
|---|---|---|---|
| lm @ 10 A | 3350 | 2700 | 2900 |
| lm @ 20 A | 6000 | 4250 | 4250** |
| W @ 10 A | 30 | 31 | 33 |
| W @ 20 A | 63 | 67 | 78** |
** May not happen in reality as discussed below.
It looks to me that on 10 A turbo they may all heat up at similar rate but the SFT90 on 20 A may be pretty short-lived with the extra 15 watts to dissipate (if the driver can indeed deliver 20 A to it at all).